From b55688dcf02d71793c6a2a66bbf1f948af81518a Mon Sep 17 00:00:00 2001
From: Will Norris <willnorris@google.com>
Date: Tue, 14 Oct 2014 16:09:18 -0700
Subject: [PATCH] set user agent header only if non-empty

---
 github/github.go      |  4 +++-
 github/github_test.go | 14 ++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/github/github.go b/github/github.go
index f4e0dc9..c9236e2 100644
--- a/github/github.go
+++ b/github/github.go
@@ -165,7 +165,9 @@ func (c *Client) NewRequest(method, urlStr string, body interface{}) (*http.Requ
 	}
 
 	req.Header.Add("Accept", mediaTypeV3)
-	req.Header.Add("User-Agent", c.UserAgent)
+	if c.UserAgent != "" {
+		req.Header.Add("User-Agent", c.UserAgent)
+	}
 	return req, nil
 }
 
diff --git a/github/github_test.go b/github/github_test.go
index 15ecce2..5fc347c 100644
--- a/github/github_test.go
+++ b/github/github_test.go
@@ -211,6 +211,20 @@ func TestNewRequest_badURL(t *testing.T) {
 	testURLParseError(t, err)
 }
 
+// ensure that no User-Agent header is set if the client's UserAgent is empty.
+// This caused a problem with Google's internal http client.
+func TestNewRequest_emptyUserAgent(t *testing.T) {
+	c := NewClient(nil)
+	c.UserAgent = ""
+	req, err := c.NewRequest("GET", "/", nil)
+	if err != nil {
+		t.Fatalf("NewRequest returned unexpected error: %v", err)
+	}
+	if _, ok := req.Header["User-Agent"]; ok {
+		t.Fatal("constructed request contains unexpected User-Agent header")
+	}
+}
+
 func TestResponse_populatePageValues(t *testing.T) {
 	r := http.Response{
 		Header: http.Header{